zvol: verify IO type is supported

ZVOLs don't support all block layer IO request types. Add a check for
the IO types we do support. Also, remove references to
io_is_secure_erase() since they are not supported on ZVOLs.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes #17803